IPM Backyard Resources

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leafcutter bee (Megachile sp.)

While some municipalities allow urban beekeeping, Edmonton's Animal Licensing and Control Bylaw allows honey bees to be kept in any agricultural zone (AG, AGU, AGI) only, and prohibits them from being kept in any other zone. Citizens can check specific zone information for Edmonton by using the interactive zoning map.

Permission may be granted for bees to be kept outside of agricultural zones for special situations, for example, temporary circumstances where bees are kept under strictly controlled conditions for educational purposes. A citizen who wishes to apply for such permission is required to submit to City Bylaw Services a written application outlining their request, with supporting information outlining why it would be in the public interest to provide for an exception to the prohibition.

Honey bees however, aren't the only bees that pollinate plants in your yard. Our general interest in backyard beneficial insects is directed towards less social species of bees and wasps, such as solitary leafcutter bees and aphid wasps, that are less threatening to the public. Pollinator blocks to attract these beneficials are an area we are looking into to support greater pollinator biodiversity and natural pest biocontrols in the backyard.

How to make a pollinator block

Start with a solid block of wood such as a round of firewood, 25 cm (10 in) in diameter or larger, which has been split in half. Make a number of holes in the split face of the block. The holes can range in size from 3-11 mm ( 1/8-7/16 in) in diameter, and as deep as the drill bit will allow. The holes should not be too close together, about 2-3 cm (1 inch) or so apart. Drill as many holes as will easily fit on the block. You can also drill holes in a stump or a post stuck in the ground. You can nail a plank onto the top of the block with 3-6 cm (1-2 in) sticking over the top the face with the holes, this will protect the holes from rain. A few species will only use blocks with this form of protection, but other species are less fussy. Place the block in some out-of-the-way part of your yard. You will probably get best results if you put the block out in the spring, but any time will work. Do not move your block once it has been positioned as the insects use landmarks to return to their hole.

What insects will use the pollinator block?

The holes in the pollinator block will likely be used by two broad categories of insects: solitary wasps, and solitary bees. Don’t worry, these insects are not aggressive like social wasps or bees can be. They are capable of stinging but you have to pick them up and handle them to get stung. Both of these types of insects will stuff the holes with enough food to bring one larva to maturity. They will then lay a single egg on that food, and use some type of material to seal the food and the larva in its protected cell. They will repeat this procedure until the hole is full of cells. A solitary bee will stuff its cells with pollen. A solitary wasp will stuff its cells with insects or spiders that have been paralyzed, but not killed by a sting of the wasp.

In either case, a larva will hatch and feed on the food left by its mother. When it has consumed the entire larder, it will change into a pupa, which will in turn change into an adult. If the adult is a male it will mate then die. If it is a female it will find a new wormhole, or pollinator block, and repeat the work of its mother.

Both solitary wasps and solitary bees are useful and interesting to have in your yard. Solitary bees will pollinate your fruits, vegetables, and ornamentals as they go about collecting pollen. Solitary wasps will hunt for bugs in your yard, in many cases they hunt for bugs that you don’t want. Different wasps specialize in hunting for different types of prey. Some hunt aphids, some stink bugs, some caterpillars, others prefer spiders or flies.

Please tell us if your your block gets used

We're very interested in learning whether your block was used or not. Please let us know at treebugs@edmonton.ca. You can tell if a hole is in use because, the end of the hole will be plugged with some material like mud, leaves or silk. You can also keep an eye on the block over the summer and observe the wasps or bees as they provision their cells. If you like you can provide additional information. For example, a brief description of where in your yard you positioned the block. How many holes are in use? Is any size of hole not used or used particularly heavily? What material did the critters use to plug the holes? Or anything else you may have observed.

Aphid wasp (Passaloecus monilicornis)

Related Documents

Before you squish, swat or spray be sure you're not destroying useful insects. Use the photos and life-sized silhouettes in this guide to help you to recognize some of the beneficial insects that live in your own backyard.